Transfer Weights does not affect one edge loop
It may be not an exact 100% answer, but i've managed to find a workaround:
I've recreated Head nr 2 by duplicating Head nr 1 and deleting all polys besides these near edge loop. Then, from Head nr 2 i took all polygons besides these around edge loop and connected it to duplicate of Head nr 1. This way, the edgeloop remained from Head nr 1, and the rest is from Head nr 2 - which gave me a Head nr 2 without problematic edgeloop. 
Problem solved, but i still don't know why it could not transfer weights properly.